Face mask with liquid and glare resistant visor
RELATED APPLICATION 
     This application is a continuation-in-part of co-pending U.S. application Ser. No. 104,807 filed Oct. 2, 1987, now U.S. Pat. No. 4,920,960. 
    
    
     TECHNICAL FIELD OF INVENTION 
     This invention relates in general to disposable medical products, and in particular to a disposable face mask with a visor to prevent liquid from contacting the eyes of a wearer. 
     BACKGROUND OF INVENTION 
     The wearing of a protective face mask has become standard procedure in many health care and other related activities. The use of a face mask is important, for example, to lab technicians during the conduction of tests, to nurses in the care of contagious patients, to physicians during surgery and to dentists working in a patient&#39;s mouth. 
     With the rapid increase in the spread of infectious diseases such as AIDS, the use of protective equipment, including masks, has become even more important. The Center for Disease Control in Atlanta, Ga., has found that AIDS can be passed by contact with body fluids. Contact of AIDS contaminated body fluids with another person&#39;s source of body fluids, i.e. eyes, nose, mouth, etc., can pass the disease. It is therefore necessary to prevent a patient&#39;s body fluids from contacting the eyes, nose and mouth of an attendant. 
     The typical previously developed protective mask covers the wearer&#39;s face from the bridge of the nose to below the chin, and is generally designed to filter out germs and other particulates. Unfortunately, a mask designed to prevent the passage of germs has little value in preventing liquids from reaching the face, and thus normal face masks provide the wearer with no protection against the patient&#39;s body fluids which may contain the AIDS virus. A face mask designed to prevent the passage of liquids from the exterior of the mask to the face of the wearer is disclosed in co-pending U.S. application Ser. No. 104,807, Oct. 2, 1987, to Hubbard et al, entitled Body Fluids Barrier Mask. The Hubbard mask prevents splashed or thrown liquids from penetrating through the mask to the wearer&#39;s mouth and nose, which is particularly important due to the aforementioned spread of AIDS. However, the Hubbard mask does not provide protection for the eyes. 
     Other protective masks, such as the Irema Shield Mate (Catalog No. SM5000), while serving to generally keep liquids from the eyes of a wearer, are susceptible to problems which detract from their effectiveness. In such masks, a solid sheet of relatively stiff clear plastic is fixed by double sided tape to opposite ends of the mask. When the mask is placed on a wearer&#39;s face, the plastic tends to remain flat and therefore pulls away from the contours of the face creating gaps. Additionally, the tendency of the visor to remain straight forces the plastic into the wearer&#39;s forehead which causes discomfort, and it is necessary to add a foam strip across the top edge of the visor to provide a comfortable fit as well as to prevent oils and perspiration from fouling the visor. The gaps between the visor and the mask are, obviously, openings for the liquids which are supposed to be excluded. 
     If the wearer of the Irema Shield Mate mask attempts to compensate for failure of the plastic to conform to their face, over compensation generally results and the plastic is creased. Plastic is susceptible to glare and reflections, and a crease in the plastic tends to increase the glare and reflections by providing more surfaces for light to strike. 
     Another liquid shield is available from Ballard Medical Products under the product name Safety Shield Kit. The Safety Shield Kit contains a protective mask, a separate eyeshield and a pair of latex gloves. The eyeshield is similar to a pair of goggles with its own elastic fastener for securing around the wearer&#39;s head. The multiple components of the Ballard Kit detract from the convenience of a one piece shield. Thus, there is a need for a convenient protective eye shield visor that will prevent the passage of liquid to the eyes of the wearer, will not crease and does not reflect glare into the eyes. 
     SUMMARY OF THE INVENTION 
     The present invention disclosed herein comprises a method and apparatus for a fluid shield visor for a face mask which substantially eliminates or reduces problems associated with prior eye shield masks. The present invention inhibits the passage of liquids through the visor to the eyes of a wearer without becoming creased or reflecting glare into the eyes of the wearer. 
     In one aspect of the present invention, a cover comprises a liquid shield visor secured to a mask that is resistant to the passage of liquids from exterior the mask to the face of the wearer. The liquid shield visor comprises clear plastic such as polyethylene or polyester having a notched cutout to facilitate conformance to various facial configurations and reduce the likelihood of reflections. Additionally, the mask may be provided with a darkened strip of material to further reduce the likelihood of reflections and glare. 
     It is a technical advantage of the present invention that the mask may be worn without the need for a separate eye protection device. It is a further technical advantage that the shield will allow the mask to conform to the contours of the face of a wearer without creasing the visor. It is a further technical advantage that the shield will reduce reflected glare. Finally, it is a technical advantage that the mask and shield combination may be stored flat. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For more complete understanding of the present invention and for further advantages thereof, reference is now made to the following Detailed Description taken in conjunction with the accompanying Drawings, in which: 
     FIG. 1 is a perspective view of a liquid resistant visor on a face mask constructed in accordance with the present invention; 
     FIG. 2 is a front plan view of a mask and visor constructed in accordance with the present invention; and 
     FIG. 3 is a front plan view of an alternate embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In FIGS. 1 and 2, like items are identified by like and corresponding numerals for ease of reference. Referring to FIG. 1, a liquid resistant shield 10 constructed in accordance with the present invention is shown in perspective. A mask 12 retards the flow of liquids from exterior the mask to the nose 14 and mouth of the wearer. A visor 16, fixed to opposite ends of the mask 12 inhibits liquids from splashing into the eyes 18 of the wearer, while allowing clear visibility to the wearer. 
     The visor 16 has a notch 20 formed therein to allow the visor 16 to bend without creasing. Bending the visor 16 allows the mask 12 to conform to the face of the wearer and still prevent liquid from splashing into the eyes 18. A darkened strip 22 may also be provided to further reduce glare. Elastic loops or tie strips 24 may be provided to removably attach the shield 10 to the head 26 of the wearer. 
     Referring to FIG. 2, the liquid resistant shield 10 constructed in accordance with the present invention is shown in plan view. The mask 12 is of the disposable layered type which is designed specifically to prevent or retard the passage of liquids from external the mask to the face of the wearer. The mask 12 is fabricated in general as disclosed in U.S. Pat. No. 4,635,628, Jan. 13, 1987, to Hubbard et al., and assigned to Tecnol, Inc., and is incorporated herein by reference. 
     Face mask 12, as shown by the cutaway portion at flap 28, has four layers of material with an external face of cover stock 30 as the outermost layer. The innermost layer, internal face 32, is constructed of a light weight, highly porous, softened, non-irritating, non-woven fabric, such as, for example, Dexter, Inc. product No. 3768. The internal face 32 is designed to prevent unwanted materials such as facial hair, loose fibers or beads of perspiration from contacting the next outermost layer which could cause a wicking effect to draw liquids therethrough. The internal face 32 also provides a comfortable surface for contact with the face of the wearer. 
     The next outermost layer comprises a barrier material 34 which is capable of differentiating between gases and liquids and may be, for example, Visqueen Film Products low density polyethylene Vispore X-6212. Non-wetting materials, such as used to form barrier 34, have small apertures which prevent liquids with a relatively high surface tension from passing therethrough yet will allow gases with a low surface tension to pass. It is preferable to have the apertures as large as possible to allow easy breathing, and yet small enough to retard the flow of liquids. The barrier material 34 is designed to freely pass gases in either direction, while restricting the passage of liquids in at least one direction. The mask 12 is constructed with the barrier material 34 positioned to restrict liquid passage from exterior the mask 12. Further description of the construction and operation of a barrier material may be found in U.S. Pat. No. 3,929,135, Dec. 30, 1975, to Thompson, assigned to Proctor &amp; Gamble Co., which is incorporated herein by reference. 
     The next outermost layer is a filtration media 36 which is, for example, melt blown polypropylene or polyester. The filtration media 36 inhibits the passage of airborne bacteria in either direction which will prevent passage of germs to and from the wearer of the mask 12. The next and outermost layer is the treated cover stock 30 which comprises, for example, a non-woven material such as cellulose fiber. The cover stock 30 is preferably chemically coated or treated, for example, by spraying with a liquid repellant, to render the cover stock 30 resistant to liquids. 
     The cover stock 30 and the filtration media 36 serve as an aid to the barrier material 34 by slowing down any liquid that may be splashed, sprayed or thrown at the mask 12. By requiring the liquid to pass through these two outer layers prior to reaching the barrier material 34, the liquid will have less pressure and the barrier material 34 will be better able to prevent passage of the liquid. 
     The mask 12 can be provided with heat sealed or ultrasonically sealed edges 38, 40 and 42. The attaching devices, such as tie strips 24, may be integral with the sealed edges 38. The edge 42 may have an included stiffening device 46 to allow molding of the mask 12 around the wearer&#39;s nose, and thus, provide a better fit. 
     Visor 16 comprises a clear plastic film such as, for example, polyester or polyethylene, and is generally dimensioned to fit across the width of face mask 12 and extend over the eyes of the wearer. The plastic material comprising visor 16 preferably has a thickness of approximately 0.005 inches and must be stiff enough to prevent collapse yet flexible enough to bend. 
     Visor 16 is fixed to opposite edges of mask 12 at bond areas 48 and 50 which may be formed by adhesives, ultrasonic seals or heat seals. The bond areas 48 and 50 are only of sufficient area (approximately 1/4 inch×1/2 inch) to secure visor 16 to mask 12. It has been found that the visor 16 more easily adapts to the contours of the face of the wearer if the bond areas 48 and 50 do not extend across the entire width of mask 12. If the bond areas 48 and 50 were to extend across the mask 12 holding the visor 16 thereto, the likelihood of creasing the visor 16 would increase, as a wearer would attempt to force visor 16 to conform to the facial contours with the mask 12. The visor 16 is placed so that approximately 1/3 of its depth D covers mask 12 which is generally desirable for the best overall performance of shield 10. In a preferred embodiment, the depth D is 41/2 inches and a width W is 71/2 inches. 
     In the approximate middle of visor 16 adjacent the mask 12, is a notch 20. The notch 20 is designed to assist the visor 16 to gradually bend around the nose of a wearer without creasing. The notch 20 resembles a key hole which has been found to be the preferred design. The notch 20 comprises a circular portion 21 and a narrow slot 23. The circular portion 21 may have a 1/4 inch radius and narrow slot 23 may have a tapered opening from 1/4 inch at A to 1/8 inch at B. The length C of notch 20 may be approximately 7/8 inch. As mask 12 is fitted over the face of a wearer, notch 20 allows for any warping, bending and/or twisting action of the visor 16. 
     Visor 16 slopes gradually upward from proximate each bond area 48 and 50 to notch 20 to form arcuate surfaces 52. The notch 20 and the arcuate surfaces 52 allow visor 16 to bend when the mask 12 is placed over the face of the wearer to approximately place the arcuate surfaces 52 in contact with a first fold line 54. The contact of fold line 54 with arcuate surfaces 52 tends to close any gaps between the visor 16 and the mask 12. 
     A darkened strip 22 of material may be applied to the top edge of mask 12 adjacent visor 16. Strip 22 may comprise any suitable material such as a treated cover stock similar to outermost layer 30 of the mask 12. The strip 22 is preferably black in color to prevent or reduce glare and reflections into the eyes 18 of the wearer. The darkened strip 22 is used in the same fashion as, for example, the blackened areas under a football player&#39;s eyes. 
     In operation, the visor 16 is secured to the mask 12 at the bond areas 48 and 50. A wearer places the mask 12 over his/her mouth and nose with the visor 16 extending over his/her eyes. The tie strips 24 are tied around the head or ears to secure the protective shield 10 to the wearer. The wearer of the shield 10 may form the mask 12 as required to conform to the shape of his/her face by molding strip 46 to the contours of the face. Due to the combination of notch 20, the bond areas 48 and 50, and the arcuate surfaces 52, visor 16 will tend to bend around the face of the wearer. Additionally, the visor 16 will not be creased, and the area between arcuate surfaces 52 and first fold line 54 will be approximately in contact with each other. Thus, the wearer is protected from thrown or splashed liquids and may wear the mask comfortably for long periods of time without excessive glare or reflections. 
     Referring to FIG. 3, an alternate embodiment of a visor generally identified by the reference numeral 60 is shown in plan view. The visor 60 is constructed and used in substantially the same fashion as described above with the exception of first and second extended sides 62 and 64. Visor 60 has a key hole notch 66 to allow for conformance to the face of a wearer. 
     Sides 62-64 are formed as an integral part of main body 68 along edges 70 and 72, respectively. Edges 70-72 are scored to allow sides 62-64 to easily fold into a transverse orientation against the side of a wearer&#39;s head. Thus sides 62-64 provide added protection to a wearer from liquids that may enter from the side. 
     It is to be understood that a visor constructed in accordance with the present invention may be fixed to a mask that is not designed to retard the flow of liquids. If so, the visor will still serve to protect the eyes from liquids, but the nose and mouth may quickly come into contact with the liquid and appropriate care should be taken. 
     Although the present invention has been described with respect to a specific preferred embodiment thereof, various changes and modifications may be suggested to one skilled in the art, and it is intended that the present invention encompass such changes and modifications as fall within the scope of the appended claims.